Valve for percussive tools



W. A. SMITH. VALVE FOR PERCUSSIVE TOOLS.

APPLICATION FILED DEC- H. 1913.

1,343, 649. Patented J um 15, 1920. 3 2,4 2.2 a 26 22 ,8 27

16 s k\\\\ xi 8 A TTORNEYS.

UNITED STATES PATENT. OFFICE.

WILLIAM A. SMITH, or EASTON', rENNsYLvANIA,r-issIeNon T INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

VALVE FOR PERGUSSIVE TOOLS.

To all whom it may concern:

Be it known that I WILLIAM A. SMITH, a citizen of the United States, residing at Easton, in the county of Northampton and State of Pennsylvania, have invented a certain new and useful Improvement in Valves for Percussive Tools, of which the following is a specification. I

This invention relates to a percussive tool primarily adapted for drilling rock but which may be utilized for any other purpose where a percussive element is rapidly reciprocated and struck against the end of a drill steel or other tool.

which is usually detached from the drill steel but which may be attached to the drill steel as in a piston drill.

The objects of the present invention are to provide a percussive tool, drill sharpener, or rock drill of the above type, commonly referred to as hammer tools, with a symmetrical diflerential piston; that is, one having two pressure areas to force the piston forwardly, and one to return the piston,

which may be reversed end for end so that when one end becomes worn or broken due to striking the end of the drill steel it may be reversed end for end and a new face pre sented to strike the drill steel at the forward end of its stroke.

Also, a further object of the invention is to provide a valve for tools of the above description which will control the admission of motive fluid to one end of the cylinder and control the exhaust of the fluid through auxilar exhaust ports from both ends of the cyl1nder, pressure fluid being admitted to the opposite ends of the cylinder through a piston controlled port and the cylinder being further supplied with a continuously open exhaust port located approximately centrally of the cylinder.

A further object of the present invention is to provide a valve forced in one direction by pressure constantly exerted against one end and thrown in the opposite direction by a fluctuating pressure against its opposite end, the valve, furthermore, being made quickly responsive to the movements of the piston by means of bleeder or leak provided within the valve.

With the above and other objects in view,

ports my invention consists of the features of construction and operation described in the fol- The tool has a cylinder in which reciprocates a plston or hammer Specification of Letters Patent. Patented Jun 1920 Application filed December 11, 1918.

Serial No. 266,286.

lowing specification and shown in the accompanying drawings, in which:

Figure 1 shows an enlarged view in sectlon of the valve especially adapted for use in the hammer type of percussive tool, the view being taken longitudinally of the valve;

Fig. 2, a longitudinal view of the complete tool, in section, showing the piston near the rear end of its stroke, and

Fig. 3, a view similarto Fig. 2, showing the location of the piston and-valve at the forward extremity of the piston stroke, in

"g'which position it strikes the drill steel.

Referrlng more particularly to the figures of the drawing, in which like references refer to like parts, 1' shows the cylinder, which, as shown in the drawings, is made in one piece, but obviously, if desired, may be made up of several separate parts. WVithin the cylinder 1 reciprocates the piston or hammer, shown generally at 2, having a centrally disposed head 3 and two extensions 44: extending from either face of said head 3 which are similar to each other, both in length and in diameter. The forward. end of the cylinder 1 is closed by a suitable front head 5 of any desired type, the one shown in the figures being purely diagrammatic. The cylinder 1 is provided with a valve chest 6 which may be integral with the cylinder 1 or made up as a separate part, in which reciprocates a cylindrical valve 7 within a suitably bored chamber 8 of the valve chest 6. Between the cylinder 1 and valve chamber 8 are a plurality'of ports 9, 10, 11, 12 and 13, each having a function presently to be described, and from the valve chamber 8 to atmosphere extends a large port 14 which is open to the atmosphere in any position of the valve 7.

Motive fluid is supplied to the drill through a suitable inlet 15 having a port 16 admitting motive fluid to the rear end of the cylinder 1 within the chamber 17 and exerting a constant pressure against the rear end of the piston extension 4;. From the chamber 17 extends a passage 18 which is in communication with an extension of the valve chamber 8 indicated at 19 and between the opening or chamber extension 19 and the rear end of the cylinder within which the head 3 of the piston operates, is the port 13 above referred to. From the position of the piston indicated in Fig. 2 it will be seen that fluid pressure may pass in the dithe piston chamber behind'the .Inain head 3 thus forcing the piston or hammer 2 for wardly, the flui'd pressure in advanceof the piston being exhausted through the ports 10 and 11 through the valve chamber 8 and out to the atmosphere through-the port 14:. As soon as the piston 2 reaches the position indicated in Fig. 3 the rear extension at of the piston 2 passes a port 20 communicating with a passage 21 which directsmotive fluid into the front end of the piston cham- 1 ber, thus..reversing the movement of' the p1ston12, and, at the same t1me,-the valve head.25 is moved to-clear port :9 by the pres-.-

sure built up through leak port 24 and the valveiis then thrown into the position indi' catedin Fig. 3 bythe pressure built up in the forwardend of the cylinder. This action of the valve takes place against the constant pressure exerted in the extension 19 of the valve chamber, by reason of the fact that the valve/chamber .8 preferably has at least twice the area ofthe chamber extension 19. During the reverse stroke ot the piston, that is, while it is moving to the rear end :01 the cylinder, the exhaust port 12;

nallyof the valve 7 as shown at 22 which is continued by a smaller passage'23in communication therewith." lfiorwardly of the passage23' is a small leak port 2a opening into the frontend otthevalve chamber 8 past the forwardhead 253 of the valve. Not only does this passage through the valve formedby'passages 22, 23 and leak port 24 serve to make the valve. more lively and quickerin itsaction but also serves .to'supply fluid to the air cushion pockets formed at either end of the valve chamber 8 and shownat 30 and 31. lVithin either of these pockets 3() and 31 motive fluid is trapped so that the valve 7 can not come in contact directly with theend walls of the valve chamber 8. 7

A second headis' provided on the valve 7 as shownat 26, and extending a short distance from the" rearend of the head 26 the valve 7 is provided with-an extension27 having approximately one half the cross sectional area of the heads 25 and 26. Just rearwardly of the head 26 extends a short leak port 28 opening into the rear end :of the valve chamber 8. As pressure is constantly exerted against the rear extension 27 of the valve 7 fluid passes continuously into the passage 22 and passage 23 and from these passages to the forward end of the valve and also to the space between the head 26and the rear-end of the valve chamber 8 i so that pressure is constantly being supplied ton chamber thereisa corresponding drop at the forward end of the valve chamber and the valve is immediately thrown toiforward position. point located a short distancefrom the ,rear end of the piston chamber 8to atmosphere, thus provldinaa short cushion charm:

ber 80 to cushion :theaction of: the valve at. the rear endof itsstroke and to which the leak port 28 tends to supply suliicient motive fluid toaid in the reversal ofthe movement of the valve, as well as aid-in CHShlOIl-.

The port 11 :is constantly ing the valve.

A port. 29 leads from a' open to atmosphere as it is not over-runby I either of the heads 25 2601? the valve? and this port has the usual functions of the cen-.

tral cylinder exhaust port usually found in crills oi": this type; that is, to exhaust a 7 large part of the motive fluid atthe end of each stroke. Port 10, which is forward of :wardstroke is overrun and thus closed by the head 260i the valve 7.

From the above the construction and operation of the tool will be clearly understood, and it is to be understood that while the present showing and description disclose only one specificembodiment of a my present invention, other forms" and m'odifications are included within the spirit and.

scope ofthe invention asexpressed'in the appended claims.

What I claim is: i r 1. Ina fluid operated reciprocating motor adaptedfora percussive tool of the hammer typeQthe combinationof a cylinder, a piston therein and a valve to control the-recip rocations of said piston, said valve being forced continuously in one direction by con stant pressure against one end and thrown in the opposite directionibya fluctuating pressure against its opposite end, said opposite end being larqer than said first mentioned end, and ha ngrzvleak port whereby fluid may begsupplied through saidlvalve to aid in the'reversal of. movement of'the valve.

2. Ina fluid operated reciprocating motor adaptedtor a percussive tool 1of-the hammer type, thezcombination of a cylinder, a piston .therein and a valve for controlling the re ciprocations of said piston, said valve being forced continuously in one direction by constant pressure against one end and thrown in the opposite direction by a fluctuating pressure against its opposite end, said oppo site end being larger than said first mentioned end, said valve controlling auxiliary exhaust ports from both ends of the cylinder and thrown toits forward position upon reduction of pressure in the forward end oi the cylinder as the piston overruns an independent central exhaust port.

3. In a fluid operated reciprocating motor adapted for a percussive tool of the hammer type, the combination of a cylinder, a piston therein and a valve to control the reciprocations of said piston, said valve being forced continuously in one direction by constant pressure against one end and thrown in the opposite direction by a fluctuating pressure against its opposite end, said opposite end being larger than said first mentioned end, and having a leak port whereby fluid may be supplied through said valve to aid in the reversal of movement of the valve, said valve controlling auxiliary exhaust ports from both ends of the cylinder and thrown to its forward position upon reduction of pressure in the forward end of the cylinder as the piston overruns an independent central exhaust port.

In a fluid operated reciprocating motor adapted for a percussive tool of the hammer type, the combination of a cylinder, a piston therein and a valve controlling the reciprocations .of said piston, said valve being forced continuously in one direction by constant pressure against one end and thrown in the opposite direction by a fluctuating pressure against its opposite end, said opposite end having a greater area than that of said first mentioned end and being provided with a leak port whereby fluid may be supplied through said valve to aid in the reversal of movement of the valve.

5. In a fluid operated reciprocating motor adapted tor a percussive tool of the hammer type, the combination of a cylinder, a piston therein and a fluid actuated valve controlling the admission of fluid to one end of the cylinder and the exhaust of a part of the motive fluid from both ends of said cylinder, said valve having a head at one end, a head near the other end and an extension extending from said second head against which fluid pressure is adapted to be con stantly exerted, and means to supply a small additional amount of fluid to said head at the end of. the valve to aid in the reversal of movement of said valve.

6. a fluid operated reciprocating motor adapted for a percussive tool of the hammer type, the combination of a cylinder, a piston my hand.

therein and a fluid actuated valve controlling the admission of fluid to one end of the cylinder and the exhaust of a part of the motive fluid from both ends of said cylinder, said valve having a head at one end, a head near the other end and an extension extending from said second head against which fluid pressure is adapted to be constantly exerted, the area of said extension being less than the area of either of said heads and means to supply a small additional amount of fluid to said head at the end of the valve to aid in the reversal of movement of said valve.

7. In a fluid operated reciprocating motor adapted for a percussive tool of the hammer type, the combination of a cylinder, a piston therein and a valve controlling the reciprocations of said piston, said valve being provided with a passage throughout its length, and with a port extending from said passage to the outer surface of said valve, said passage and port being constantly open to fluid pressure and thereby permitting fluid to pass through said valve continuously and build up pressure in the valve chamber when the valve is at either end of its stroke to aid in throwing the valve to its opposite position.

8. In a fluid operated reciprocating motor adapted for a percussive tool of the hammer type, the combination of a cylinder, a piston therein and a valve controlling the reciprocations of said piston, said valve being provided. with a passage throughout its length, and with a port extending from said passage to the outer surface of said valve near one end, said passage and port being constantly open to fluid pressure and thereby permitting fluid to pass through said valve continuously and build up pressure in the valve chamber when the valve is at either end. of its stroke to aid in throwing the valve to its opposite position and to cushion the valve at the end of its stroke. 9. A reciprocating motor operated by fluid pressure, comprising a cylinder having a piston therein, said piston having difi'erential diameters and a rearward extension, a valve having differential diameters and a rearward extension, constant pressure being exerted against the rearward extensions of said valve and piston, said valve being controlled by the exhaust from the front end of the cylinder, and thrown to its forward position as pressure is exhausted from the front end of the cylinder and thrown to its rearward position as pressure is admitted to the forward end of the cylinder.

In testimony whereof I have hereunto set YVILLIAM A. SMITH. lVitness:

Bonner L. AMBROSE. 

